Conventional airplane combustion engines which drive propellers generally require “tune-ups” on various occasions such as upon release from the factory, at regular maintenance intervals once placed in operation, and perhaps at other times. Such tune-ups typically involve making adjustments to particular operating characteristics of the airplane engines. For example, suppose that an airplane or engine manufacturer has just completed manufacture of an airplane or engine. Prior to releasing the engine to the customer, the manufacturer thoroughly calibrates, tests and inspects the engine to confirm that the engine properly operates. Along these lines, the manufacturer sets or modifies various operating parameters of the airplane engine such as the fuel mixture, the idle speed and the oil pressure, among other things.
To adjust an airplane engine's fuel mixture, a skilled technician typically exposes the carburetor or fuel injection section of the engine (e.g., by removing an engine cover or a panel of the airplane body which covers that section of the engine) so that the technician has hands-on access to the mechanical linkage responsible for controlling the fuel-air mixture as it passes into the combustion section of the engine. The technician then starts the engine and allows the engine to drive the propeller. While the engine drives the propeller (thus enabling the engine to drive the actual load), the technician is capable of manually adjusting a thumb wheel of the mechanical linkage to increase or decrease the richness of the fuel mixture in order to optimize engine performance. In particular, the technician places a hand over the mechanical linkage so that the technician's fingers firmly engage depressions of the thumb wheel. The technician then manually rotates the thumb wheel in either a first direction (e.g., clockwise) to increase the richness of the fuel mixture, or the opposite direction (e.g., counterclockwise) to decrease the richness of the fuel mixture.
The technician may modify other engine features in a similar manner (i.e., while in direct physical contact with the engine) while the engine is running and driving the propeller. For example, the technician may manually grasp and turn a second thumb-actuated component or use a wrench or screw driver (e.g., rotate a thumb wheel, a thumb screw, an adjustment bolt, etc.) to change the idle speed of the engine. Additionally, the technician may manually grasp and turn a third thumb-actuated component or wrench/screw-driver actuated component to change the oil pressure within the engine.